It is possible to produce water onboard of a craft that is driven by a power plant such as a turbine. This is particularly true for aircraft, however, water may also be produced onboard of watercraft or ground vehicles such as trains and autonomous stationary units by using fuel cells or another suitable process. In order to assure the flight safety as well as the operational safety of an aircraft and to provide comfort for the passengers, it is required that certain redundancies are available. For this purpose it is necessary that the individual system components are interlocked with one another in their operation. The conventional separation between water or wastewater systems on the one hand and the climate or cabin air systems on the other hand, and the separation between energy producing systems on the one hand and hydraulic or pneumatic systems on the other hand is not practical and not advantageous where fuel cells are used.